Analog Devices Inc./Maxim Integrated DS1811R-5-U

Overview

DS1811R-5-U from Maxim Integrated (now Analog Devices) is a 5V precision voltage-monitoring reset IC with open-drain output, designed to automatically restart microprocessors after power failure. It asserts an active-low reset for 150 ms after V_CC returns to tolerance (4.50–4.75 V trip range), features an internal 5.5 kΩ pull-up resistor, and operates from –40°C to +85°C in SOT-23 package.

For engineers reviewing the DS1811R-5-U datasheet, DS1811R-5-U pinout, DS1811R-5-U application, or DS1811R-5-U equivalent, key selection criteria include guaranteed 4.62 V typical V_CC trip point, 150 ms reset timeout, open-drain RST output compatibility with 3.3 V/5 V logic, and SOT-23 footprint suitability for space-constrained embedded control systems.

Technical Context

The DS1811R-5-U integrates a temperature-compensated voltage reference and comparator to detect V_CC deviations outside its ±5% tolerance window (4.50–4.75 V). Upon out-of-tolerance detection, it immediately asserts RST; upon recovery, it holds RST active for 100–300 ms (typ. 150 ms) to ensure system stabilization.

Its open-drain RST output supports wired-OR configurations and interfaces directly with microcontroller reset inputs. The internal 5.5 kΩ pull-up eliminates external components in standard 5 V systems, while I_OL ≥ 10 mA ensures robust drive capability into capacitive loads up to 10 pF.

Key Specifications

Pinout & Package

SOT-23-3 surface-mount package (2.92 mm × 1.3 mm × 1.0 mm), RoHS-compliant, moisture sensitivity level 1.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar voltage-monitoring reset applications.

Compared with TPS3808G01DBVR and MAX809SEUR+T, the DS1811R-5-U offers integrated pull-up and guaranteed 150 ms timeout without external components, making it optimal for cost-sensitive, space-constrained 5 V microcontroller reset applications where open-drain flexibility is needed.

Availability

DS1811R-5-U is available at Aetrix Electronics and suitable for industrial automation, smart metering, automotive body electronics, and point-of-sale terminal designs requiring stable component supply and long-term manufacturability.

Supply support for DS1811R-5-U includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Maxim Integrated, now part of Analog Devices, designs precision analog and mixed-signal ICs for industrial, automotive, communications, and computing applications.

The DS1811R-5-U belongs to the EconoReset™ family of supervisory circuits, engineered to replace discrete reset solutions with single-chip voltage monitoring and timed reset assertion for 5 V embedded systems.

FAQ

What is the exact V_CC trip voltage range for DS1811R-5-U?

The DS1811R-5-U has a guaranteed V_CC trip point range of 4.50 V (minimum), 4.62 V (typical), and 4.75 V (maximum) at –40°C to +85°C. This ±5% tolerance around 4.63 V ensures reliable reset assertion during 5 V supply sags while avoiding false triggers from normal ripple or noise.

Does DS1811R-5-U require an external pull-up resistor on the RST pin?

No, DS1811R-5-U includes an internal 5.5 kΩ pull-up resistor on the open-drain RST output. This eliminates the need for an external component in standard 5 V systems. An external pull-up is only required if interfacing to logic voltages exceeding V_CC, such as 12 V or 3.3 V with level-shifting constraints.

How long does DS1811R-5-U hold the reset signal active after V_CC recovers?

The DS1811R-5-U holds RST active for 100–300 ms after V_CC returns to tolerance, with a typical duration of 150 ms. This guaranteed timeout allows microprocessor clock circuits, PLLs, and power supplies sufficient time to stabilize before releasing reset, preventing erratic startup behavior.

Can DS1811R-5-U operate with supply voltages below 5 V?

Yes, DS1811R-5-U operates across a V_CC range of 1.2 V to 5.5 V. However, its 4.50–4.75 V trip point is optimized for 5 V systems. At lower V_CC, the device remains functional but may not assert reset until the supply falls below the fixed threshold - making it unsuitable as a general-purpose low-V_CC monitor.

What is the maximum sink current capability of the DS1811R-5-U RST output?

The DS1811R-5-U RST output can sink at least 10 mA when pulled to 0.4 V, per its DC electrical characteristics. This ensures compatibility with microcontroller reset inputs having typical leakage currents and trace capacitance, supporting reliable reset assertion even under moderate capacitive loading (≤10 pF).